Safe deposit box lock



NOV- 17. 1964 R. 1'. |.|s ETAL 3.157.043

SAFE DEPOSIT Box Locx Filed Sept. 29. 1961 4 Sheets-Sheet l RQY T. ELLIS STEPHEN A. D MAN ATTORNEYS Nov. 17, 1964 R T; E| |s ETAL 3,157,043

SAFE DEPOSIT BOX LOCK Filed Sept. 29. 1961 4 Sheets-Sheet 2 8| 46 IIS ll 7| 4 54 72 e5 25 4 55 ||':3 72 \48 "-99 .1 1,' l .l |45 86 89 90 B7 9| 95 96 97 98 FIG. 3 2 26 24 l2 27 25- `3 4a 52 49 |24 3o 2a 7J |09 |o73l29 loe FIG. 4

|NvEN-roRs ATTORNEYS Nov. 17, 1964 R. T. ELLIS ETAL 3,157,043

SAFE DEPOSIT BOX LOCK Filed Sept. 29. 1961 4 Sheets-Sheet 3 NVENTORS 2 ROY T. ELL|s STEPHEN A. DENMAN BYJ' ,6W j

2O |37 lOl lll 95 l lO ATTORNEYS Nov. 17, 1964 Filed sept. 29. 1961 R. T. ELLIS ETAL SAFE DEPOSIT BOX LOCK 4 Sheets-Sheet 4 FIG. I4

FIG. I6

INVENTORS ROY T- E LLI S STE PHEN A. DENMAN BYJ' ,f1/w,

ATTORNEYS United States Patent O 3,157,043 SAFE BEPOSH lX LCK Roy T. Ellis, 29-43 W. Apple St., Ear/ton 2, Ghia, and

Stephen A. Denman, liqna, @hing said Denman assignor to said Ellis Filed Sept. 29, 1961, Ser. No. 141,771 S Claims. (Cl. 'M -339) This invention relates to a lock and especially to a lock for a safety deposit box or the like.

The lock has a housing with a retractable bolt therein. There are a plurality of iloating primary tumblers within the housing, and retraction of the bolt is controlled by the positions of the primary tumblers. The lock has a guard key nose and a customer key nose located toward the opposite ends of the primary tumblers, and the proper sequence oi the proper keys must be operated in both key noses before the tumblers can be positioned to release the bolt for retraction. The tumblers have no iixed pivots, but, instead, they rock about a key nose when raised by a key in the other key nose.

To be unlocked the lock requires operation of one or more keys in the guard key nose. At the guard key ends, the primary tumblers have a plurality of slots. A lever is pivotally supported by the housing and has an end that is movable with these slots only when the guard key ends of the tumblers are positioned so that the slots are aligned. The other end of the pivotal lever is positioned to operate as a block opposite a lug on the bolt, and until the lever moves into the slots, it blocks retraction of the bolt.

There are a plurality of secondary tumblers equal in number to the primary tumblers. The secondary tumblers are pivotally supported by the housing and completely surround the customer key nose. Hence, the secondary tumblers prevent the detection of the positions of certain parts of the primary tumblers by the introduction of probes and the like into the customer key nose. The Secondary tumblers also prevent picking of the lock by other means that will be explained.

This lock has the foregoing blocks against retraction of the bolt, but it also incorporates structure that allows the lock to be set in a special unlocked condition for initial delivery or the lock and for each change in control of the lock as represented by the holder of one or more keys. This special condition incorporates positioning of the several blocks in such positions that the bolt can be held in a retracted position without having been operated upon by keys so that the lock can be installed without keys. The keys may be delivered in separate sealed packages to be opened only by a customer after the lock is installed upon a Safety deposit box and the box rented. In particular, the bolt of the lock has a lug that is normally blocked by the edges of the primary tumblers, but tits within slots in the primary tumblers when these tumblers are aligned by the proper sequence or key operation. However, the lug is so mounted that it may be moved and held away from interference with the primary tumblers with the bolt retracted. In this position, the lug is biased toward its normal position and is released to that normal position upon initial extension of the bolt by the customers key or keys. Once the lug has moved to its normay position, it cannot be returned to the special installation position by the use of probes or the like because the secondary tumblers block the use of such probes.

In this special installation condition of the lock, the lever that is adjacent the guard key end of the tumblers is also held in a position free of the lug on the bolt. This lever, likewise, is biased toward its normal blocking position and attains that position upon initial extension of the bolt.

This lock is adaptable to more than one mode of opera- 3,l57,ll43 Patented Nov. l?, 1954 ICC tion. It may be operated by a guard key followed by a customer key; it may be operated by the guard key or customer key in the guard key nose and then by the customer key in the customer key nose; or it may be operated by one or more separate keys additional to the guard key in the guard key nose followed by the customer key in the customer key nose. This last operation is desirable, tor example, when there are co-renters of the same box, each With a different key, and each renter wants to be present when the deposit box is opened.

in conventional locks, the slot positions of the tumblers can be determined by sound detection of their resonance characteristics. This lock has means to prevent such resonance-reading of the lock.

An obiect of the invention is to provide a versatile lock that may be built for operation by a variety of key sequences and which has novel means for preventing picking the lock.

Another object of the invention is to provide a lock having oating tumblers associated with two key noses wherein the ends of the iloating tumblers must be properly positioned by keys before the bolt can be retracted.

A further object is to provide a lock of the foregoing kind that requires a key to be left in place in each of the two key noses as a prerequisite to opening of the bolt. An additional object is to provide a lock in which the guard key cannot be removed until the lock is closed. Another object is to provide such a lock that may require as many as three keys for its operation.

Another object of the invention is to provide a lock for a safety deposit box that has means normally positioned for blocking retraction of the bolt, but wherein the lock can be set in a special installation condition with the bolt retracted, without the use of keys so that the lock can be installed without keys and the customer key or keys can be kept in a sealed package until handed to the customer.

Another object is to provide a lock that has means for preventing detection of the positions of parts of the lock that must be set prior to the retraction of the bolt, which detection is easy in conventional locks bythe use of probes and the like introduced into the customer key nose.

Yet another object of the invention is to provide a lock that is operable by keys inserted through two separate key noses with a plurality of tumblers that must be properly positioned by keys in these key noses, wherein the proper positioning ot the tumblers is controlled by keys in both key noses.

A further object of the invention is to prevent reading of the guard key by probes inserted in the guard key nose when the locking bolt is retracted and there is no key in the guard key nose.

Still another object of the invention is to provide a lock that has a plurality of tumblers with slots in them that must be aligned before the bolt can be retracted, with means for preventing detection of the positions of the slots by sound detection means.

Another object of the invention is to provide a lock that must be unlocked before it can be removed from its installed position on a safe-ty deposit box.

Further objects and advantages will be apparent from a more detailed description of the invention.

In the drawings:

FIGURE 1 is a side elevation view of the lock with the cover lremoved and the bolt retracted.

FIGURE 2 is a side elevation view of the lock with the cover removed and showing the lock in the special installa-tion condition;

FIGURE 3 is a side elevation view of the lock with the cover removed and the bolt extended;

FIGURE 4 is a View in section taking along the line 4--4 of FlGURE 3, but with the cover in place;

FIGURE 5 is a view in section taken along the line 5 5 of FIGURE 4, but with the primary and secondary tumblers removed;

FIGURE 6 is a view in section taken along the line 6-6 of FIGURE 5;

FIGURE 7 is a view in section taken along the line 7-7 of FIGURE 5;

FIGURE 8 is a view in section taken along the line 8 8 of FIGURE 5;

FIGURE 9 is a view in section taken along the line 9--9 of FIGURE 5;

FIGURE 10 is a rear view of the bolt and primary lug assembly;

FIGURE 11 is a back view of the front cover shown removed from the lock housing;

FIGURE 12 is a view in section taken along the line 12-12 of FIGURE 4;

FIGURE 13 is a side elevation View of the customer key nose;

FIGURE 14 is a back view of the customer key nose;

FIGURE 15 is a side elevation view of the guard key nose;

FIGURE 16 is a back view of the guard key nose;

FIGURE 17 is a fragmentary isometric View of a primary tumbler showing the slot for a biasing spring; and

FIGURE 18 is a fragmentary side elevation view of only those parts of the lock that relate to the lock reioval feature of the invention.

In general, the lock has a housing 2) with a removable cover 21. The cover 21 has a pair of sleeve openings 22 and 23 for receiving a pair of key noses Z4 and 25. The key nose 24 has a slot 26 for receiving a key. The key nose 25' has a similar slot 27 for receiving one or more keys. The left hand nose 2e' is for a customer key and the right hand nose is for a guard key (plus another key or keys, as will be explained.)

rThese key noses 2A and 25 have ends 2S and 29, respectively, of reduced size that are journalled within recesses and 31 in the back wall of the housing. (See FIG. 4.) The key noses 24, and 25 have enlarged heads 32 and 33. Spaced from the tops of the heads 32 and 33 are a pair of annular shoulders 34 and 35, respectively, that extend somewhat more than half the distance around the circumference of the heads 32 and 33. The .terminations of the shoulder 34 define a pair of stops 36 and 37. The terminations of the shoulder 35 define a pair of stops 38 and 3R.

The stops 36 and 37 on the customer key nose cooperate with a corresponding stop projection dit cast in the inner part of the sleeve 22 to define the limits of rotation of the key nose 2e. Likewise, the stops 3S and 39 cooperate with a pair of stop projections el and 42 cast in the inner part of the sleeve 23 to define the limits of rotation of the key nose 2S.

A locking bolt i5 (FIG. 10) is slidably mounted against tracks on the back wall of `the housing 20. The locking bolt 4S has a projecting end 46 that moves through an opening #i7 in the left side wall of the housing 26.

As shown particularly in FIGURES 5 and 10, primary lug d8 is pivotally fastened by a stud i9 to the rear side of the bolt 45. This lug 48 has a blocking part 5% that extends through the arcuate portion 511 of a hole 52 in the bolt 45. The front face of the bolt has an arcuate recess S3 immediately forward of the hole 52 that allows the blocking part of the lug 4S to pivot freely. This blocking part has an upper horizontal portion 5f!- and a rearward vertical portion 55. rIhis shape may be varied somewhat, but it is desirable that the blocking part Sti be higher at the rearward end than at the forward end for reasons to appear.

On the rearward side of the bolt 45, the lug [i8 has an upwardly extending projection 56 that is engaged by the long end 57 of a spring 53. The spring is fastened to the bolt t5 by a stud S9 and held in place by an arcuate boss 60 on the bolt. The other end of the spring is bent to form a hook 61 and is captured within a slot 62 in the bolt. The spring 5S biases the primary lug 43 toward the position shown in FIGURES 5 and 10, which is limited in a counterclockwise direction (as viewed in FIGURE 5) by a ledge 63 on the rear side of the bolt extension 46 that is engaged by an extension 64 of the horizontal portion 54 of the blocking part 59. The primary lug has an extension 65 that extends beyond the hook 61 on the spring 5S. The hook 61 is in the path of movement of the extension 65 and thereby blocks the pivotal movement of the primary lug 48 in a clockwise direction from the position shown in FIG- URE 5. Hence, once the primary lug 48 is in the nornal position shown in FIGURES 5 and 10, it remains there until changed by the factory. The purpose of the pivotal mounting of the primary lug will appear hereinafter.

There are a plurality of primary tumblcrs within the housing 29. These tumblers are positioned rearwardly of the bolt 45, and normally the forward edges 7l of at least some of a plurality of the primary tumblers 70 block the primary lug 48 to prevent retraction of the locking bolt.

The tumblers 7d are iioating tumblers, e.g., have no fixed pivots. There is a primary tumbler pin 72. fixed to the housing, but each of the primary tumblers has an elongated slot 73 through which the pin 72 extends to guide the primary tumblers only.

While the edges 7l of the primary tumblers normally 'lock the primary bolt lug 4S, each of these tumblers has a trapezoidally shaped slot 74 that are shaped to receive the portions 54 and 55 of the lug 43 when all of the slots 74 are aligned and opposite the lug 48. The several slots 74 are positioned at different heights with respect to one another.

The primary tumblers 70 normally rest upon the top of the key nose 25, but are spaced from the key nose 24 by, and rest upon, a plurality of secondary tumblers 75.

The secondary tumblers are pivotally mounted upon a pin 76 that is attached to the housing 2G, and the secondary tumblers completely surround the customer key nose 2d, as shown in FIGURE 3. The holes '77 in the secondary tumblers through which the customer key nose projects are irregularly shaped, with an extension 78 to allow free insertion of a key. There is also a key tooth bearing surface 79 for each secondary tumbler, and an extension 89 to prevent blocking of the secondary tumbler by the key nose Z4.

There is a slot 81 within the top of each primary tumbler 73. The middle of a bent wire spring 82 is positioned within each slot, with the ends of the springs bearing against the top of the housing. These springs SZ bias the primary tumblers 7G downwardly and press them against the secondary tumblers 75. Hence, each of the primary tumblers follows the movement of the secondary tumbler immediately below it.

Each of the primary tumblers 70 has a guard key bearing surface S5 above the guard key nose 25. The proper key (or keys) within the guard key nose 25 directly engages at least some of the guard key bearing surfaces S5 on the primary tumblers to raise the guard ends of the primary tumblers. The proper key within the customer key nose 24 raises at least some of the secondary tumblers which, in turn, raise the corresponding primary turnblers to align and position the slots 74 for receiving the primary bolt lug 48. There are, however, additional prerequisites to this positioning of the primary tumblers.

rEhe bolt 45 has a lower arm Se, and a secondary bolt lug 87 mounted to pivot about a pivot pin 3 on this. The secondary bolt lug 87 is normally positioned by a torsion spring 89 against a stop 9i? projecting outwardly adjacent the bottom edge of the bolt 45. The lug 37 has an inwardly bent end 91 for a purpose to appear.

There is a bolt release lcver SFS having a hub 96 that is pivotally mounted on a pin 97 attached to the housing. The bolt release lever 95 is biased to rotate in a counterclockwise direction by a torsion spring 9S. The bolt release lever 95 has a laterally projecting pin 99 at its upper end, and the pin 99 normally engages the right hand edges of at least some of the primary tumblers '70 and prevents rotation of the bolt release lever 95 in a counterclockwise direction away from the position illustrated in FIGURE 3.

The bolt release lever has a blocking end 101i that is positioned opposite the bent end 91 of the secondary bolt lug 87 when the bolt release lever is in the position of FIGURE 3. The lever 95 also has a rod 101 above the blocking end 100 and spaced rearwardly thereof. The rod 1111 is also rearward of the end 91 of the secondary bolt lug 87. It has a function that will be explained hereinafter.

Each of the primary tumblers 70 has a trapezoidal guard end slot 102, and when the slots 162 are aligned and properly positioned by the action of a key or keys within the guard key nose 25, the pin 99 can slip into the slots 192, allowing the bolt release lever 95 to pivot to the position illustrated in FIGURE l. In this position of the bolt release lever 95, the secondary bolt lug 87 releases the locking bolt i5 because the blocking end 91 of the lug can slide over the blocking end 10u of the bolt release lever, as is apparent in FIGURES 1 and 5.

The lock may be designed so that more than one key must be operated in the guard key nose before the slots 1112 are aligned. For this operation, the right hand edges 105 of the primary tumblers 71B may be extended to a number of different lengths according to the number of different keys required to operate the guard key end of the lock. The lock illustrated requires two such keys (one of which may be the customer key), and the dotted line of FIGURE 3 shows that the right hand edge 1115 of one or more of the tumblers 7@ is further to the left than the edge or edges 1115 of the other tumblers. Consequently, when one key (for example, the customer key) is turned within the guard key nose 25, the teeth of that key bear against the guard key bearing surfaces 85 of these primary tumblers having extended edges 1115 (furthest to the right). The proper first key will align the slots 152 of these primary tumblers. However, because the positions of the slots 162 of the remaining primary tumblers are not affected by the first key operated within the nose 25, the bolt release lever 95 is blocked from complete counterclockwise rotation by the abutment of the pin 99 against the edges 1195 of the remaining primary tumblers. 1n this condition, the blocking end 190 of the bolt release lever 95 still blocks the secondary bolt lug 87.

When the second (guard) key is operated within the nose 25, its teeth operate against the guard key bearing surfaces S5 of the remaining primary tumblers 70 that still obstruct the pin 99. The guard key aligns the slots 102 of these remaining primary tumblers, and the pin 99 can then move all the way into all the slots 102. When the proper sequence of the proper keys is used, the secondary bolt lug 87 is unblocked.

Whether or not the guard key end of the lock is operable by a single key or by a plurality of keys, the primary tumblers 7u are released from the pin 99 of the bolt release lever 95 only upon counterclockwise return rotation of the last such key. There is a reset cam 106 rotatably mounted near the rearward end 29 of the guard key nose 25. The reset cam 1116 is positioned between the back Wall of the housing and a shoulder 1117 on the guard key nose 25 that terminates the reduced end 29. The end 29 of the key nose 25 is journaled within a'lug 10S on the back wall of the housing.

The reset cam 156 has a slot 109 in it for receiving the end of a long key. Shorter keys, like the customer key and any keys inserted into the guard key nose 25 before the last key, will not reach the slot 1119. The last t5 key (usually the guard key) is a longer key and is the only key that will operate the reset cam 106.

There is a trip dog 111B mounted for rotation about the pin 97 and biased by a trip dog return spring 111 against a trip dog stop 112 that depends from the bolt release lever 95.

The reset cam 156 has an actuating surface 113 for engaging a retracting surface 11d on the trip dog 110. There is a reset surface on the reset cam 1116 for engaging a return surface 115 on the trip dog 11). Thus, while the last, and longest key inserted within the guard key nose 25, when rotated clockwise, establishes the aligned position of any theretofore unaligned primary tumbler slots 152 (allowing the boit release lever to rotate to the position shown in FIGURE l), it also rotates the reset cam 1195 in a clockwise direction. This rotation of the reset cam causes it, through engagement between the actuating surface 113 and the retracting surface 114, to rotate the trip dog 111i in a counterclockwise direction against the force of the trip dog return spring 111 and away from the trip dog stop 112. The lengths of the reset cam 1116 and tie trip dog 11) between these operating surfaces is such that the reset cam releases the trip dog prior to the compiete clockwise rotation by the last key, and the trip dog snaps back against the trip dog stop 112 under the action of the trip dog return spring 111. Thereafter, when the last key in the guard key nose is turned counterclockwise, the reset surface 115 of the reset cam engages the return surface 116 on the trip dog and forces the trip dog to rotate in a clockwise direction. As the trip dog rotates, it operates through the trip dog stop 112 to rotate the bolt release lever in a clockwise direction. During this action, the engagement between the reset surface 115 and the return surface 116 is maintained long enough to revolve the pin 99 beyond the right side of the openings of all the slots 1112. At this point, the primary tumblers 70 fall downward against the nose 25 under the force of the tumbler return springs S2. The nal counterclockwise rotation of the reset cam causes it to slip past the return surface 116 on the trip dog 110. Then the bolt release lever 95 can, under the force of the spring 9S, return to its normal position, as illustrated in FIGURE 3.

In order to properly position the reset cam 156, there is a detent lever 1125, pivotally mounted about a pin 119 supported at the right side wall of the housing. The detent lever 113 has a right angle notch 125 that engages a corner 121 of the reset cam 165. The detent lever 11S is biased against the reset cam 156 by a spring 122 to assure alignment of the slot 109 with the key slot 27 in the guard key nose 25. The detent lever 118 is forced out of engagement with the corner 121 when the reset cam 156 is rotated.

Referring to FIGURE 5, there is a bolt operating cam 124 with a tongue 125 that fits within the slot 26 in the customer key nose 24. Thus, the bolt operating cam 12e rotates with the customer key nose 24. The bolt operating cam has a bolt retracting surface 127 for engaging the edge 125 of an extension 129 on the locking bolt 45. The initial contact between the bolt retracting surface 127 and the projection surface 125 occurs only after about a ninety degree clockwise rotation of the cam 124. The bolt operating cam 124 also has a bolt actuating surface 139 that engages a return surface 131 on the locking bolt when the customer key nose 24 is rotated in a counterclockwise direction. The surfaces 13@ and 131 make contact only after about a ninety degree counterclockwise rotation of the cam 124.

The locking bolt 45 is limited to horizontal movement by a guide comprising a tongue 134- on the bolt that slides within a groove 135 in the rear Wall of the housing.

The bolt 45 has a bolt extension 137 having a slanted upper surface 133. When the bolt release lever 95 is pivoted clockwise, and the secondary lug 87 pivoted counterclockwise (away from the blocking end the rod lill can ride over the bolt extension i3? and rest upon the surface i133, as illustrated in FIGURE 2. This is one of the special installation settings that is performed at the factory prior to shipping the lock for installation. The other setting is the pivoting of the primary bolt lug 48 in a clockwise direction against the force of the spring 5S to the position illustrated in FIGURE 2. When the bolt release lever and the primary bolt lug are in these positions, the bolt can be retracted without the use of keys. Once the bolt is retracted, the portion of the primary bolt lug 43 rests upon the top surfaces of some of the primary tumblers 7d and is held there against the force of the spring 5S because v/hen the bolt is retracted, the top surfaces of these primary tumblers extend forward of the arc through which the lug portion S5 pivots, and the bolt release lever is held in position with the rod Titll resting upon the surlace 13S of the bolt extension 137.

The lock is shipped in this bolt-retracted condition for instaliation. The keys are packaged separately, preferably in a lead lined package to prevent )t-ray detection. The lock is installed without the keys, and the key package remains unopened until the box is rented. Thus the customer is assured that no bank employee has seen or had an opportunity to duplicate the customer key.

After the box is rented, the bolt is extended by turning the customer key in the customer key nose. As the bolt extends, it moves the rearmost edge of the rear portion 55 of the primary bolt lug l along the upper surfaces of the primary tumblers to a point beyond the edges '7l of the primary tumblers 7G, and the spring 5t; pivots the primary bolt lug to the position shown in FIGURES 5 and l0. Once there, the end 6l of the spring 58 blocks the lug extension 65 and prevents clockwise rotation of the primary bolt lug. Also, as the bolt t5 moves forwardly, it draws the bolt extension i3? away from the rod lill. Then the spring 93 pivots the bolt release lever 95 in a counterclockwise direction until the pin 9* bears against the edges of the primary tumblers. Thereafter, the lock is normally operated.

There are a plurality of randomly spaced, randomly shaped, and randomly sized holes Mil in the primary tumblers '70 to prevent detection of the tumbler slots by means of sound detection. The holes ldd confuse the resonance characteristics of the tumblers and prevent reading of the slot positions of the tumblers by sound detection apparatus.

The back wall of the housing 20 has a plurality of screw holes tll through it, positioned adjacent the corners of the housing. The cover 2l has a plurality of corner notches M2 opposite the holes M1. The lock is fastened to a door D (see FIGURE 18), with the cover 2li disposed against the door, by means of screws 143 that extend through the notches T42. The screws 143 have heads 141ithat are of larger diameter than that of either the holes T ft or the notches 142. However, the holes Ml are large enough to receive the operating end of a screwdriver.

In the past, with conventional locks, it has been easy to remove a lock from an opened vault door and to replace that lock with another. lf a guard opens one of these conventional locks with his and a customers key, thereafter returning the customer key to the customer while leaving the vault door open, the temporary absence of the customer for about thirty seconds atfords guard suiiicient time to replace the lock with a similar lock. lf the guard has the customer key to the substituted lock, he can open the door to the safety vault once the customer has left.

The lock of this invention prevents such substitution by a guard or other unauthorized person.

The lower left corner E45 of the bolt t5 (as viewed in FIGURE 3) is extended to lie between the head of the adjacent screw 143 and the back of the lock housing when the bolt is extended. When the bolt 45 is extended, the corner M5 thereof prevents access to the adjacent screw M3 by a screwdriver inserted through the lower left hole Ml. Since the customer key is alway returned to the customer when he leaves his opened vault, and since the counterclockwise rotation of the customer key forces the bolt operating cam 124 to extend the bolt 45, the guard alone cannot remove the lock when the bolt is extended.

When authorized removal of the lock is necessary, the bolt 45 can be retracted, retracting with it the corner 14S to provide access to the head of the screw 143 through the hole Ml. When the screw is threaded away from the door D, it cannot be removed through the adjacent hole 141 because the head 14d of the screw is too large. Therefore, the screw is retained within the housing and blocks extension of the bolt. With the bolt retracted, the customer key is turned in its key nose. However, even in this condition, the lock cannot be removed. FGURE i3 shows a key K inserted into the customer key nose. It can be seen that the handle of this customer key extends beyond the edge of the sleeve 22 and overlies a part of the door D. Therefore, when the bolt is retracted to provide access to the lower left screw 143, the lock cannot be removed from the door because the handle of the customer key prevents withdrawal of the sleeve 22 from the door. Therefore, the customer key must be cut off before the lock can be removed.

The screw M3 is longer than the distance between the door D and the side of the bolt corner 145 that faces the door. Therefore, the housing cannot be removed by unthreading the screw until its head is just even with the bolt 45, because there will then be some screw threads within the door. The lock cannot be pulled part of the way away from the door, because of the customer key against the front side of the door.

This requirement that the customer key be cut assures that the lock will be returned to the manufacturer when it is removed to receive a new factory made customer key. Upon recepit of such shipment, the factory can change the tumblers of the lock so that it operates with a different customer key. Then when the lock is returned, it cannot be operated by its previous customer who may have had a duplicate key made.

Operation This lock operates by means of one or more keys turned within the guard key nose 25 and a single key turned within the customer key nose 24. Assuming that the lock is in the condition illustrated in FIGURE 3, with the bolt 45 extended, a key is inserted into the guard key nose 25 and is rotated. As that key is rotated, its teeth are arranged to bear against the key bearing surfaces S5 of those primary tumblers having extended right hand edges 'L05 While it will be appreciated that the slots T02 are not initially aligned, the teeth of the key are of irregular shapes so that upon rotation of the key, the right ends of the primary tumblers 70 that have the extended edges 105 are raised so as to bring the slots of these rst raised primary tumblers into alignment opposite the pin 99. When this is accomplished, the pin 99 snaps a short distance into those slots 102 that are thus aligned until it is obstructed by the edges 105 of the not yet aligned primary tumblers. The pin 99 then holds the right ends of the now aligned tumblers elevated, even when the rst key is removed.

Since the rst key introduced into the key nose 25 is not long enough to reach the slot M99 in the reset cam 1%, that first key, when rotated counterclockwise, and removed, will not pivot the bolt release lever 95, and the pin 39 will remain part of the way within the aligned slots 102.

Also at this point in the operation, the movement of the pin 99 part of the way within the slots 3.92 does not free the blocking end ltltl of the lever from obstructive position relative to the secondary bolt lug S7.

When the second or guard key is introduced into the guard key nose 25, it moves within the slot 109 of the reset cam 106 since it is a longer key. When this second key is turned in a clockwise direction, it aligns the slots 102 of the remaining primary tumblers, allowing the pin 99 to be moved all the way into the slots 1612 under the action of the torsion spring 98. It then holds the right ends of all of the tumblers 70 in upward position. This full movement of the piu 99 lowers the blocking end 10) of the bolt release lever 95 to a position below and out of alignSment with the bolt lug S7, as shown in FIGURES 1 and As the guard key ends of the primary tumblers 70 are raised by keys operated in the guard key nose 25, the slots 74 are lowered because, in this action, the iioating primary tumblers pivot about their rest positions on top of the secondary tumblers 75. If desired, one or more of the slots 74 may initially be above the lug 48, so that when the left ends of the primary tumblers are moved downwardly as aforesaid, these particular slots move into positions opposite the primary bolt lug 4S. For these tumblers, the customer key introduced into the customer key nose 24 will have teeth arranged to be ineffective upon the already positioned primary tumblers.

The slots 74 of the remaining primary tumblers are aligned and positioned opposite the primary bolt lug 48 by rotation of the customer key in the customer key nose during which rotation the customer key teeth engage the edges 79 of the secondary tumblers 75 and rock the same about the pivot 76, and the secondary tumblers, in turn, engage the inner edges of the primary tumblers and lift their left ends, while their right ends rock about the arm 99 in the slots 192 of the primary tumblers. Thereafter, continued rotation of the customer key nose causes the bolt retracting surface 127 of the bolt operating cam 124 to engage the projecting surface 128 on the bolt 45 and retract the projecting end 46 of the locking bolt.

A special feature of the secondary tumblers is the fact that they completely surround the customer key nose 24. This construction of the secondary tumblers prevents reading of the slot positions by probes inserted through the customer key nose, and also prevents false displacements of the bolt release lever 95 and the secondary bolt lug 87 by probes inserted in the customer key nose.

To return the lock to locked position, the customer key in the customer key nose 24 must be removed irst because the bolt extension 137 is positioned above the rod 101 and prevents clockwise rotation of the bolt release lever 95. Therefore, the reset cam 196 cannot rotate past the trip dog 110 which is held in place by the stop 112. This is a further safeguard that prevents removal of the guard key while the customer key is still in place.

As the customer key nose is rotated in a counterclockwise direction, the bolt operating cam 124 engages the return surface 151 of the bolt 45 and re-extends the projecting end 46 of the bolt. At that same time, it releases the primary tumblers from their engagement with the primary bolt lug, and these tumblers fall against the upper edges of the secondary tumblers 75.

The total arc of rotation of the key nose 24 in either direction is about 135. However, the locking bolt is either retracted or extended only during about the last 45 of rotation of the key nose 24 and the bolt operating cam 124. This lost motion in the rotation of the bolt operating cam is intentional, and the trapezoidal shapes of the slots 74 on the primary tumblers 7i), as well as the short height at the front of the primary bolt lug 48, are irnportant in association with this lost motion. Because of the size of the slots 74 relative to the primary bolt lug, the tumblers can rock about the tops ofthe secondary tumblers 75. And the extent of rocking that is possible is such that after all keys have been removed from the guard key nose 25, and the primary tumblers have dropped against the guard key nose, the re-extension of the locking bolt 45 upon counterclockwise rotation of the customer key does not raise the primary tumblers from the guard key nose Z5. In addition, the angular lost motion of the bolt operating cam 124 allows the tumblers to be lowered by the customer key prior to movement of the wider part 55 of the lug toward the narrower part of the slots 7 4.

The fact that the primary tumblers remain at rest upon the guard key nose 25 prevents the reading of the guard key by the insertion of probes into the guard key nose. If the tumblers were lifted from the guard key nose upon counterclockwise rotation of the customer key, their relative positions could be determined by a probe in the guard key nose, and then, by projecting the relative distances of the guard key nose and the customer key nose from the slots 74, the exact configuration of the guard key could be calculated.

When the guard key nose 25 is rotated counterclockwise, the reset cam 196, which had moved past the trip dog and allowed the trip dog 119 to return against the stop 112 engages the return surface 116 of the trip dog 110 and presses the trip dog against the stop 112. The consequent movement of the stop 112 causes the bolt release lever 95 to pivot and retract the pin 99 from the slots 102. In this event, the wire springs 82 press the guard key ends of the primary tumblers against the guard key nose 25. When the bolt 45 is extended, the secondary bolt lug S7 does not interfere with the return of the bolt release lever 95.

One of the important features of the present invention is the anti-resonance feature here exemplified by the presence of the holes in the primary tumblers. With conventional safe deposit box locks there are usually a definite number, such as live to eight tumblers containing the slots corresponding to the slots 74. There may be more than one set of tumblers. All of the various different locks are developed from combinations of these live to eight, more or less, tumblers. Consequently, if someone obtains one or two locks of a particular make and style, he can obtain a full set of tumblers having the full range of slot positions. Conventional tumblers which are identical have closely similar resonance characteristics.

Therefore, one having a complete set of tumblers may, with appropriate instruments determine the sound picture or oscillogram characteristic of each tumbler with a particular slot position. Having made this preliminary determination, the lock picker has only to use instruments that permit him to develop the resonance characteristics of each of the tumblers chosen for the particular lock of that make that he wishes to open, and to compare each with pictures of the resonance characteristics of the known tumblers. When a record of the sound characteristics of a hidden tumbler is found to be nearest to one of the predetermined oscillograph patterns, the operator knows the slot arrangement of that tumbler. With miniature resonance detecting and recording instruments, with the later use of an oscilloscope, this operation can be performed with no diiiiculty.

Various changes and modications may be made within the process of this invention as will be readily apparent to those skilled in the art. Such changes and modifications are within the scope and teaching of this invention as defined by the claims appended hereto.

What is claimed is:

l. ln a lock, a housing, a bolt within the housing slidable between retracted and extended positions, a plurality of tumblers within the lock having forward edges, a key nose opposite the tumblers for receiving a key to move the tumblers, each tumbler having a slot cut in its forward edge and normally out of alignment with at least some of the other slots, a lug pivotally supported by the bolt opposite the forward edges of the tumblers to prevent retraction of the bolt when the slots are unaligned, the lug being receivable within the slots when they are aligned, the tumblers being movable by a proper key in the key nose to align the slots, the lug being pivotal to a position beyond the forward edges of the tumblers to allow retrac- 1 l' tion of the bolt without alignment of the slots for installation of the lock without the use of a key.

2. The lock of claim l wherein the housing has holes through it to permit mounting of the lock by screws and the bolt has an extension that covers at least one of the bolt holes when the bolt is extended.

3. In a lock having a housing and a bolt therein slidable between retracted and extended positions, a lug pivotally supported by the bolt, a plurality of tumblers within the housing having forward edges with slots in the forward edges, the forward edges of the tumblers being opposite the lug and the slots being normally unaligned, a key nose extending into the housing, the tumblers being positioned adiacent the key nose for movement by a key turned in the key nose to align the slots, the lug being receivable within the aligned slots to permit retraction of the bolt, the lug being pivotal to a position away from interference with the forward edges of the tumblers to allow setting of the lock in a bolt-retracted condition without alignment of the slots, a spring for biasing the lug to its normal position, means for holding the lug ,in its position away from interference with the forward ed es of the tumblers when the bolt is retracted and for automatically releasing the lug when the bolt is thereafter extended, and releasable means for blocking pivotal movement of the lug to its position away from interference with the forward edges of the tuinblers.

4. A lock having a housing, a bolt within the housing and movable between retracted and extended positions, a plurality of tumblers within the housing normally blocking retraction of the bolt, a guard key nose adapted to receive a guard key and a customer key nose adapted to receive a customer key, the key noses being positioned adjacent the tumblers so that each tumbler is moved by both the guard and customer keys, the tumblers being so arranged as to require movement by both the guard key and the customer key before the bolt can be retracted, and means to prevent removal of the guard key from its key nose until the customer key has been removed from its key nose.

5. A lock comprising a housing, rst and second key noses extending into the housing, a bolt slidable within the housing between retracted and extended positions, a lever for sliding the bolt when a proper key is turned within the first key nose, a plurality of tumblers normally positioned to block retraction of the bolt, each tumbler being positioned in operative relation to both key noses and being movable to unblocking position upon the turning of proper keys within both key noses, and means to prevent removal of a key from the second key nose when the bolt is retracted.

6. A lock comprising a housing, a bolt slidable within the housing between retracted and extended positions, a key nose projecting into the housing for receiving a key, a plurality of tumblers within the housing normally positioned to block retraction of the bolt, but movable to unblocking positions upon operation of a proper key within the key nose, a plurality of screws for mounting the housing to a mounting surface, means on the bolt blocking access to at least one of the screws when the bolt is extended and means preventing removal of the key from the keynose when the bolt is retracted thereby requiring cutting of the key as a prerequisite to removal of the lock from the mounting surface.

7. The lock of claim 6 wherein the lock is mounted upon a door with a hole through the door to provide access of the key to the key nose, the key having a part on it that will not tit through the hole in the door, means to prevent removal ot the screw from the housing when it has been withdrawn from the door, and means to prevent extension of the bolt when the screw has been withdrawn from the door.

8. A lock comprising a housing having a bolt slidable therein between retracted and extended positions, a key nose, a plurality of tumblers positionable by a key in the key nose, a bolt lug pivotally supported by the bolt, the bolt lug being pivotal to an operating position in relation to the tumblers such that the tumblers normally block retraction of the bolt until moved by a proper key in the key nose, the bolt lug being movable to a position out of interference with the tumblers, so that the bolt can be retracted without using a key, at least one of the tumblers having an edge positioned when the bolt is retracted to hold the bolt lug in the position out of interference with the tumblers, and spring means biasing the bolt lug to automatically pivot the bolt lug toward and hold the bolt lug in the said operating position upon extension of the bolt and consequent freeing of the bolt lug from the said tumbler edge.

References Cited by the Examiner UNITED STATES PATENTS 23,113 3/59 Powers 70-355 536,510 3/95 Cooke 70-339 1,432,720 lO/ZZ hIOSely 70-339 l,439,042 l2/22 Varnum et al 70-339 2,524,696 lO/SO Ellis 70-339 3,103,806 9/63 Ellis et al 70-339 ALEERT H. KAMPE, Primary Examiner. 

4. A LOCK HAVING A HOUSING, A BOLT WITHIN THE HOUSING AND MOVABLE BETWEEN RETRACTED AND EXTENDED POSITION, A PLURALITY OF TUMBLERS WITHIN THE HOUSING NORMALLY BLOCKING RETRACTION OF THE BOLT, A GUARD KEY NOSE ADAPTED TO RECEIVE A GUARD KEY AND A CUSTOMER KEY NOSE ADAPTED TO RECEIVE A CUSTOMER KEY, THE NOSES BEING POSITIONED ADJACENT THE TUMBLERS SO THAT EACH TUMBLER IS MOVED BY BOTH THE GUARD AND CUSTOMER KEYS, THE TUMBLERS BEING SO ARRANGED AS TO REQUIRE MOVEMENT BY BOTH THE GUARD KEY AND THE CUSTOMER KEY BEFORE THE BOLT CAN BE RETRACTED, AND MEANS TO PREVENT REMOVAL OF THE GUARD KEY FROM ITS KEY NOSE UNTIL THE CUSTOMER KEY HAS BEEN REMOVED FROM ITS KEY NOSE. 